BACKGROUND: Gamma hydroxybutyrate (GHB) and its precursors (GHB-P) are major causes of drug-related coma in the U.S. Dramatic and rapid changes in patterns of GHB use are associated with increasing morbidity and mortality. Despite this, little is known about the determinants of adverse outcomes following use. STUDY HYPOTHESIS: Adverse outcomes following GHB use are multi- factorial. We propose to delineate the role of psychosocial and physical factors as predictors of adverse outcomes in GHB use; including socio-demographic factors, attitudinal issues, specific exposures (GHB v. GHB-P), and pharmaco-dynamics. EXPERIMENTAL PLAN: Component C1: California Poison Control System (CPCS) surveillance will capture demographics, exposure, and outcomes for 600 exposure subjects over the study period. Product and blood/urine testing will confirm GHB or its precursors. Component C2: Structured interviews of 390 exposed subjects, recruited from the CPCS surveillance cohort, will collect supplemental data not available from passive surveillance alone. Component C3: Controlled human exposures in 144 volunteers will compare disposition kinetics and effects of GHB and 1,4 butanediol, examining dose-dependence, gender differences, ethnic differences, genetic influences and interaction with ethanol. Component C4: Focus groups will explore the motivating factors for GHB use and abuse. Nine focus groups (54 subjects) from 3 sources (an adverse experience group from C2; experimentally exposed subjects from C3; and a community-based sample of GHB users without adverse events) will evaluate differences in hazard perception, acquisition, settings and use outcomes. Analyse s: Multivariate modeling will have sufficient power to detect RR's less than 2.0 for key risk factors and outcomes in the 20 percent incidence range. Human exposures will use paired and repeated-measures comparisons with power to detect change slightly greater than one standard deviation. SIGNIFICANCE: This study, by elucidating predictors of adverse outcomes from GHB use will provide data important for clinical and public health interventions to reduce morbidity associated with this drug of abuse.